• 6 versus 12 months of adjuvant trastuzumab for HER2-positive early breast cancer (PERSEPHONE): 4-year disease-free survival results of a randomised phase 3 non-inferiority trial.

      Sherwood Forest Hospitals NHS Foundation Trust; PERSEPHONE Steering Committee and Trial Investigators (2019-06-06)
      BACKGROUND: Adjuvant trastuzumab significantly improves outcomes for patients with HER2-positive early breast cancer. The standard treatment duration is 12 months but shorter treatment could provide similar efficacy while reducing toxicities and cost. We aimed to investigate whether 6-month adjuvant trastuzumab treatment is non-inferior to the standard 12-month treatment regarding disease-free survival. METHODS: This study is an open-label, randomised phase 3 non-inferiority trial. Patients were recruited from 152 centres in the UK. We randomly assigned patients with HER2-positive early breast cancer, aged 18 years or older, and with a clear indication for chemotherapy, by a computerised minimisation process (1:1), to receive either 6-month or 12-month trastuzumab delivered every 3 weeks intravenously (loading dose of 8 mg/kg followed by maintenance doses of 6 mg/kg) or subcutaneously (600 mg), given in combination with chemotherapy (concurrently or sequentially). The primary endpoint was disease-free survival, analysed by intention to treat, with a non-inferiority margin of 3% for 4-year disease-free survival. Safety was analysed in all patients who received trastuzumab. This trial is registered with EudraCT (number 2006-007018-39), ISRCTN (number 52968807), and ClinicalTrials.gov (number NCT00712140). FINDINGS: Between Oct 4, 2007, and July 31, 2015, 2045 patients were assigned to 12-month trastuzumab treatment and 2044 to 6-month treatment (one patient was excluded because they were double randomised). Median follow-up was 5.4 years (IQR 3.6-6.7) for both treatment groups, during which a disease-free survival event occurred in 265 (13%) of 2043 patients in the 6-month group and 247 (12%) of 2045 patients in the 12-month group. 4-year disease-free survival was 89.4% (95% CI 87.9-90.7) in the 6-month group and 89.8% (88.3-91.1) in the 12-month group (hazard ratio 1.07 [90% CI 0.93-1.24], non-inferiority p=0.011), showing non-inferiority of the 6-month treatment. 6-month trastuzumab treatment resulted in fewer patients reporting severe adverse events (373 [19%] of 1939 patients vs 459 [24%] of 1894 patients, p=0.0002) or stopping early because of cardiotoxicity (61 [3%] of 1939 patients vs 146 [8%] of 1894 patients, p<0.0001). INTERPRETATION: We have shown that 6-month trastuzumab treatment is non-inferior to 12-month treatment in patients with HER2-positive early breast cancer, with less cardiotoxicity and fewer severe adverse events. These results support consideration of reduced duration trastuzumab for women at similar risk of recurrence as to those included in the trial.
    • Acute presentation of a partially obstructing laryngeal tumour: adjuvant agents to gaseous induction of anaesthesia.

      Thomas, Carolyn (2018-07)
      We present the case of a 53-year-old man who attended our emergency department with stridor. He had recently undergone investigation for possible glottic cancer. We discuss the airway management of such a case. We believe this to be the first description of propofol target controlled infusion and clonidine to supplement a sevoflurane gas induction, in order to obtund response to intubation while maintaining spontaneous ventilation. We also consider how airway interventions may impact prognosis and need to be considered.
    • Antibiotic prophylaxis in breast surgery: a meta-analysis to identify the optimal strategy to reduce infection rates in breast surgery.

      Akbari, Amir R
      Intro: Breast surgeries are an increasingly frequent operation, with an exponential rise in breast cancer diagnoses, and women opting for cosmetic surgeries. SSIs are the most common post-operative complication with many negative consequences including sepsis and even death. These are treated with prophylactic antibiotics prior to surgery. Breast surgery is currently defined as 'clean', although literature indicates that the infection rate is higher than should be expected for this classification. The aim of this meta-analysis is to evaluate whether pre-operative antibiotics reduce SSI frequency and which class of antibiotics achieve the best reduction. Methods: A literature search through online libraries was used to find clinical trials investigating pre-breast-surgery antibiotics and SSI frequency. These were grouped all together and separately by class of antibiotics. Additionally studies investigating breast cancer surgeries and non-cancer surgeries were grouped separately. A forest-plot was created for each group to calculate an estimated effect, these were then compared against each other. Results: Use of antibiotics resulted in a reduction in SSI frequency by 3.55% overall, and reduced frequency in all types of surgeries performed. Cephalosporins reduced SSI frequency by 2.23%, Beta-lactamase inhibitors 4.17% and macrolides achieved the greatest effect with a 14.58% reduction. Conclusion: This meta-analysis proves that antibiotics reduce SSI frequency in breast surgery and supports the notion to remove the 'clean' classification. This definition may result in failure to provide prophylaxis, resulting in patients suffering from preventable SSIs and their negative consequences. Macrolides were the most effective followed by beta-lactamase inhibitors and cephalosporins, this may be implemented in structuring new guidelines favouring use of macrolides before conducting breast surgery.
    • Delineating outcomes of patients with diffuse large b cell lymphoma using the national comprehensive cancer network-international prognostic index and positron emission tomography-defined remission status; a population-based analysis.

      Haynes, Andrew (2016-04)
      The recently devised National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI) appears superior to the revised IPI (R-IPI) in delineating outcome in diffuse large B-cell lymphoma. We examined the outcome of a population-based cohort of 223 consecutive patients treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone) or R-CHOP-like immuno-chemotherapy between January 2005 and December 2011 by both the NCCN-IPI and R-IPI, and further stratified outcome by the achievement of both computerized tomography (CT) and positron emission tomography (PET)-CT complete remission (CR), with the latter reassessed using blinded central review by an independent nuclear medicine and radiology specialist. The NCCN-IPI was superior to the R-IPI in identifying patients at very high risk of systemic and/or central nervous system relapse. Notably, both the NCCN-IPI and the R-IPI remained strongly predictive of relapse irrespective of CT or PET-defined remission status following R-CHOP. Patients with high-risk NCCN-IPI scores (6) have a dismal outcome following R-CHOP therapy regardless of PET-defined response to R-CHOP. Moreover, such patients appear refractory to salvage chemotherapy and thus require alternative therapeutic approaches, although age and performance status may, for many patients, preclude the safe delivery of a primary intensified regimen. By contrast, patients with NCCN-IPI 1-5 who achieve PET-CR following R-CHOP have excellent outcomes and may merit reduced follow up frequency.
    • EBV-positive mucocutaneous ulceration.

      Reza, M; Qureshi, A (Annals of the Royal College of Surgeons of England, 2021-11)
      Ulceration of the oral cavity is common and a frequent reason for referral to secondary and tertiary centres. Epstein-Barr virus (EBV)-related mucocutaneous ulceration, however, is a rare cause of oral ulceration that has been described only recently. Histologically these lesions resemble lymphomas; however, their management and prognosis differ significantly. We present a case of EBV-induced oral ulceration and discuss the diagnosis and management of and available literature for the condition, which was treated successfully through conservative measures alone.
    • Education and Training Needs in Radiation Oncology in India: Opportunities for Indo-US Collaborations.

      Morgan, David (2015-12)
      Purpose: To conduct a survey of radiation oncologists in India, to better understand specific educational needs of radiation oncology in India and define areas of collaboration with US institutions. Methods and Materials: A 20-question survey was distributed to members of the Association of Indian Radiation Oncologists and the Indian Brachytherapy Society between November 2013 and May 2014. Results: We received a total of 132 responses. Over 50% of the physicians treat more than 200 patients per day, use 2-dimensional or 3-dimensional treatment planning techniques, and approximately 50% use image guided techniques. For education needs, most respondents agreed that further education in intensity modulated radiation therapy, image guided radiation therapy, stereotactic radiation therapy, biostatistics, and research methods for medical residents would be useful areas of collaboration with institutions in the United States. Other areas of collaboration include developing a structured training module for nursing, physics training, and developing a second-opinion clinic for difficult cases with faculty in the United States. Conclusion: Various areas of potential collaboration in radiation oncology education were identified through this survey. These include the following: establishing education programs focused on current technology, facilitating exchange programs for trainees in India to the United States, promoting training in research methods, establishing training modules for physicists and oncology nurses, and creating an Indo-US. Tumor Board. It would require collaboration between the Association of Indian Radiation Oncologists and the American Society for Radiation Oncology to develop these educational initiatives.
    • Effectiveness of percutaneous vacuum-assisted excision (VAE) of breast lesions of uncertain malignant potential (B3 lesions) as an alternative to open surgical biopsy

      Yemm, Julia
      Traditionally B3 breast lesions are treated surgically, but overtreatment is a concern, as the majority have a final benign diagnosis. A national screening program introduced vacuum-assisted excision (VAE) for managing B3 lesions in late 2016. This retrospective study aimed to assess the outcomes associated with this approach.
    • Environmental and social benefits of the targeted intraoperative radiotherapy for breast cancer: data from UK TARGIT-A trial centres and two UK NHS hospitals offering TARGIT IORT.

      Morgan, David (2016-06)
      Objective To quantify the journeys and CO2 emissions if women with breast cancer are treated with risk-adapted single-dose targeted intraoperative radiotherapy (TARGIT) rather than several weeks' course of external beam whole breast radiotherapy (EBRT) treatment. Setting (1) TARGIT-A randomised clinical trial (ISRCTN34086741) which compared TARGIT with traditional EBRT and found similar breast cancer control, particularly when TARGIT was given simultaneously with lumpectomy, (2) 2 additional UK centres offering TARGIT. Participants 485 UK patients (249 TARGIT, 236 EBRT) in the prepathology stratum of TARGIT-A trial (where randomisation occurred before lumpectomy and TARGIT was delivered simultaneously with lumpectomy) for whom geographical data were available and 22 patients treated with TARGIT after completion of the TARGIT-A trial in 2 additional UK breast centres. Outcome measures The shortest total journey distance, time and CO2 emissions from home to hospital to receive all the fractions of radiotherapy. Methods Distances, time and CO2 emissions were calculated using Google Maps and assuming a fuel efficiency of 40mpg. The groups were compared using the Student t test with unequal variance and the non-parametric Wilcoxon rank-sum (Mann-Whitney) test. Results TARGIT patients travelled significantly fewer miles: TARGIT 21681, mean 87.1 (SE 19.1) versus EBRT 92591, mean 392.3 (SE 30.2); had lower CO2 emissions 24.7kg (SE 5.4) vs 111kg (SE 8.6) and spent less time travelling: 3h (SE 0.53) vs 14h (SE 0.76), all p<0.0001. Patients treated with TARGIT in 2 hospitals in semirural locations were spared much longer journeys (753 miles, 30h, 215kg CO2 per patient). Conclusions The use of TARGIT intraoperative radiotherapy for eligible patients with breast cancer significantly reduces their journeys for treatment and has environmental benefits. If widely available, 5 million miles (8000000km) of travel, 170000 woman-hours and 1200 tonnes of CO2 (a forest of 100hectares) will be saved annually in the UK.
    • eQTL set-based association analysis identifies novel susceptibility loci for Barrett's esophagus and esophageal adenocarcinoma

      Jankowski, Janusz
      Background: Over 20 susceptibility single-nucleotide polymorphisms (SNPs) have been identified for esophageal adenocarcinoma (EAC) and its precursor, Barrett's esophagus (BE), explaining a small portion of heritability. Methods: Using genetic data from 4,323 BE and 4,116 EAC patients aggregated by international consortia including the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON), we conducted a comprehensive transcriptome-wide association study (TWAS) for BE/EAC, leveraging Genotype Tissue Expression (GTEx) gene expression data from six tissue types of plausible relevance to EAC etiology: mucosa and muscularis from the esophagus, gastroesophageal (GE) junction, stomach, whole blood, and visceral adipose. Two analytical approaches were taken: standard TWAS using the predicted gene expression from local expression quantitative trait loci (eQTLs), and set-based SKAT association using selected eQTLs that predict the gene expression. Results: While the standard approach did not identify significant signals, the eQTL set-based approach identified eight novel associations, three of which were validated in independent external data (eQTL SNP sets for EXOC3, ZNF641 and HSP90AA1). Conclusions: This study identified novel genetic susceptibility loci for EAC and BE using an eQTL set based genetic association approach. Impact: This study expanded the pool of genetic susceptibility loci for EAC and BE, suggesting the potential of the eQTL set based genetic association approach as an alternative method for TWAS analysis.
    • Evaluation of a novel paper-based algorithm for breast family history risk assessment.

      Milburn, Nikki; Jahan, Ali; Elamin, Ghassan (EJSO: European Journal of Surgical Oncology, 2022-05)
    • Factors associated with psychological distress for couples facing head and neck cancer: A systematic literature review

      Biswas, Sanchia (2021-08)
      Objectives: Cancer patients in supportive relationships display improved health and survival outcomes. Identifying factors that might respond to intervention for Head and Neck Cancer (HNC) dyads is important as HNC patients and their partners experience heightened distress. This article systematically reviewed and evaluated the research findings and methodological quality of studies which identified factors influencing psychological distress for couples facing HNC. Methods: PsycINFO, Medline, and CINAHL were searched. Studies were included if they used validated psychological distress measures and quantitative data collection methods. Eleven studies satisfied inclusion criteria. Results: Studies identified factors associated with the psychological distress experienced by couples facing HNC, with substantial effect size variation. These factors included clinical, sociodemographic, relational, and psychological variables. Factors associated with increased psychological distress included disease burden, reduced social contact, perception of reduced relationship quality, and less adaptive/assimilative coping although the effect sizes displayed considerable heterogeneity. Overall, studies possessed good methodological quality but generally could have been improved by minimising the risk of non-response bias and fully reporting relational characteristics. Conclusions: The implications of these results for clinical practice and future research are discussed. Further research is recommended to report effect sizes more consistently for both dyad members to gain greater insight into couple-level distress and to perform moderator analyses to identify which variables influence the magnitude of psychological distress.
    • Faecal occult blood testing screening for colorectal cancer and 'missed' interval cancers: are we ignoring the elephant in the room? Results of a multicentre study.

      Aggarwal, Smeer; Dharmavaram, Sridhar; Menon, Achyuth; Dube, Mukul; George, Anil Thomas (2017-05)
      AIM: Biennial faecal occult testing (FOBT) is used to screen for colorectal cancer throughout the United Kingdom (UK). Interval cancers are tumours that develop in patients between screening rounds who have had a negative FOBT. Through a multicentre study, we compared demographics of patients with interval cancers, FOBT screen detected cancers and cancers that developed in patients who chose not to participate in the screening programme. METHOD: Five hundred and sixteen colorectal cancers were detected in the screening age group (60-74 years) population in three United Kingdom NHS Hospitals over two years. 127 (25%) were interval cancers, 161 (31%) were screen-detected and 228 (44%) were cancers that developed in patients who had declined FOBT. The interval cancer group had a higher incidence of right sided cancers (38% vs 29% and 24%), a higher proportion of high tumour stages (Dukes C&D) (70% vs 53% and 33%) and a shorter time from diagnosis to death (10 months vs 13 months and 24 months) compared to patients who had declined the FOBT and the FOBT screen detected cancers. Of all the patients studied, those with right sided interval cancers had the worst outcome. A quarter of the colorectal cancers diagnosed in our study were interval cancers. Patients with right-sided interval cancers had the highest proportion of Dukes C and D tumours coupled with the shortest survival time after diagnosis when compared with all the other groups. This article is protected by copyright. All rights reserved.
    • Finding the needle in the haystack: the diagnostic accuracy of the faecal immunochemical test for colorectal cancer in younger symptomatic patients

      Foley, Stephen (2021-10)
      Aim: Detection of early onset colorectal cancer is challenging, and remains a rare diagnosis amongst younger people with gastrointestinal symptoms. We investigated whether faecal immunochemical testing (FIT) could identify younger patients at higher risk of colorectal cancer or serious bowel disease including colorectal cancer, inflammatory bowel disease or advanced adenomas. Methods: A subgroup analysis was performed of symptomatic patients under 50 years of age (<50) from the NICE FIT study, a multicentre, prospective diagnostic accuracy study of FIT conducted between October 2017 and December 2019. The diagnostic accuracy of FIT for colorectal cancer and serious bowel disease was investigated in younger patients at different faecal haemoglobin (f-Hb) cut-offs of 2, 10 and 150 µg blood/g faeces (µg/g). Results: Early onset colorectal cancer was diagnosed in 1.5% (16/1103) of younger symptomatic patients. The sensitivity of FIT for younger patients aged <50 was 87.5% (95% CI 61.7%-98.4%), 81.3% (54.4%-96.0%) and 68.8% (41.3%-89.0%) at f-Hb cut-offs of 2, 10 and 150 µg/g, respectively. The positive predictive value for colorectal cancer increased from 4.2% (2.3%-6.9%) to 11.5% (5.9%-19.6%) at cut-offs of 2 and 150 µg/g, while the positive predictive value for serious bowel disease increased from 31.3% (26.3%-36.5%) to 65.6% (55.2%-75.0%) at the same cut-offs. The negative predictive value of FIT for colorectal cancer remained above 99.5% at all cut-offs. Conclusion: Detectable f-Hb on FIT in symptomatic younger patients may indicate referral for investigation of colorectal cancer and serious bowel disease.
    • Glove Port Transanal Excision of Rectal Tumors an Alternative Method for Rectal Tumor Excision: Single Center Experience.

      Dharmavaram, Sridhar (2017-08)
      Aim: Transanal minimal invasive surgery has been practiced for several years for excision of rectal tumors however there is no standard consensus about its applications. This minimally invasive approach helps in avoiding major rectal resections and its associated risk of mortality and morbidity.The aim of this study is to describe a single center experience with transanal glove port excision of rectal tumors which are not amenable to colonoscopic excision. Materials and Methods: Between the years 2011 and 2014, 9 patients underwent glove port excision of rectal tumors located within 15 cm from the anal verge. Glove port was constructed using circular anal dilator, standard surgical glove and a wound protector retractor; regular laparoscopic instruments were used. The median follow-up period was for 18 months (range, 9 to 27 mo) and all patients had flexible sigmoidoscopy for follow-up to look for any recurrence of the tumors. Results: All patients underwent transanal excision of rectal tumors successfully using glove port device and laparoscopic instruments. Full thickness excision of the tumor was performed in all patients and there was no significant postoperative morbidity. The final histology of 6 patients was benign and the remaining 3 patients had malignancy reported in the specimen. During the follow-up period between 12 and 18 months 3 patients had a recurrence of the polyp which was removed endoscopically without the need for any further surgical intervention. Conclusions: Glove port excision of rectal tumors is a feasible alternative to conventional surgical treatment for large benign rectal tumors.What does this paper add to the literature?This article demonstrates that performing local excision of rectal tumors can be achieved safely at a lower cost using simple platforms that are constructed locally like the glove ports. It also highlights the benefits of using the available laparoscopic kits to perform the procedure while making use of the previously acquired skills.
    • Imaging techniques in breast cancer

      Beremauro, Stebia (Surgery, 2022-01)
      Imaging is the mainstay in breast cancer diagnosis, with mammography being the primary screening tool used to detect small/asymptomatic cancers. Symptomatic patients undergo triple assessment which includes a clinical assessment, imaging and, if indicated, an image-guided biopsy for histological diagnosis. We discuss current and emerging breast imaging techniques used in breast cancer care. These include mammography, digital breast tomosynthesis, ultrasound and magnetic resonance. We also discuss image-guided biopsy and miscellaneous image-guided interventions that influence the management of breast cancer care.
    • Impact of MRI on high grade Ductal Carcinoma Insitu (HG DCIS) management, are we using the full scope of MRI?

      Dakka, Mahmoud (2017-10)
      Introduction: Preoperative assessment of pure Ductal Carcinoma Insitu (DCIS) is essential in the surgical planning. The role of Magnetic resonance imaging (MRI) has long been debated. The impact of MRI on the management of High Grade (HG) DCIS was assessed, whether it accurately captures the true size of this entity in comparison to conventional imaging, and, if MRI use would reduce the number of re-excision surgery.Method: Ninety-one consecutive patients with HG DCIS, who were identified from a prospectively collected data at Kettering General Hospital between April 2011 and December 2015. All patients had preoperative MRI scan in addition to the standard breast imaging. This was compared to a control group of consecutive patients (n=52) which was obtained from a period just before 2011. Impact on surgical planning and number of surgeries for each patient was compared. The size of HG DCIS estimated by MRI was compared to the final histological size. Secondary outcomes included change of initial surgical plan and detection of occult contralateral breast cancer.Results: MRI group had 91 patients with median age of 63. Seventy percent of which presented through the screening program. The overall sensitivity of MRI to detect HG DCIS was 77% (70/91) with a false negative rate FNR of 23% (21/91). Therefore, 70 patients only were included in the data analysis. The control group included 52 screening patients with comparable baseline characteristics. Re-excision (or completion mastectomy) rates were higher in the control group 26% compared to 8% in the MRI group (P-value 0.012). MRI use correctly converted the initial plan of breast conservation to mastectomy in 9 patients (13%). Five patients had additional ipsilateral malignant features (7%).Occult contra lateral disease, was diagnosed in 2 patients (3%).Conclusion: This study suggests that MRI could be an important tool in reducing the re-excision rates in the surgical management of HG DCIS. Although still controversial, selective MRI imaging can be useful in the preoperative diagnosis and evaluation of HG DCIS. Case by case discussion at MDT is crucial. Wider adaptation of MRI when indicated in the assessment of breast lesions with proper correlation to histology postoperatively is a key in improving our MRI interpretation skills, helping us to exploit the full scope of this useful tool.
    • Incidental finding of prostate cancer in transurethral resection of prostate (TURP) specimens: A retrospective analysis from a tertiary care hospital in Pakistan

      Memon, Shahbaz Mustafa (The Pan African Medical Journal, 2021-05)
      Introduction: incidental prostate cancer findings reflect the great burden of prostatic cancer across the globe. Our 10 year retrospective analysis aimed to identify the incidence and clinic-pathologic features of prostate cancer incidentally detected in patients undergoing transurethral resection of the prostate (TURP) for benign prostatic hyperplasia (BPH), and to estimate the clinical value of pathologic review of all TURP specimens. Methods: after excluding patients with a known diagnosis of prostate cancer prior to TURP a total of 2,386 men (ages 25-98) were identified by pathology (TURP) specimens. Yearly incidences, Gleason score, grade, pathologic stage were recorded for all incidental prostate cancer patients. Results: a total of 256 (10.7%) patients were found to have prostate cancer. Mean Age was 68.51±9.22 years. T1a and T1b stage prostatic carcinoma was found in 9.9% and 90.1% of these patients respectively. Forty-nine percent (49%) patients had higher Gleason scores (>7). After subtracting average incidences between 5-year intervals, a statistical rise of almost 4% was found. Conclusion: our analysis concludes that a large proportion (10.7%) of patients had incidental prostate cancer and the incidence was increasing in recent years in Pakistan and in comparison, to Asian countries. In Pakistan there is a scarcity of updated national cancer registries. The growing incidence of high Gleason scores requires keen and prompt attention. The diverse ethnic and socioeconomic background of patients propels their propensity towards loss of follow up with already limited tertiary healthcare institutes in Pakistan. This pathologic review of TURP specimens is valuable for Asiatic and non-Asiatic populations.
    • Modelling the radiobiological effect of intraoperative X-ray brachytherapy for breast cancer using an air-filled spherical applicator

      Morgan, David (2016)
      PURPOSE: We present a framework, in which we compare a conventional standard dose of 50 Gy in 25 fractions with accelerated partial breast irradiation (APBI) using electronic brachytherapy (eBT). We discuss how radiobiological modelling enables us to establish a framework, within which we can compare external beam radiotherapy (EBRT). This leads to a determination of the shell of isoeffect in breast tissue, at which very low kV eBT can be considered to be clinically equivalent to standard EBRT. MATERIAL AND METHODS: To estimate relative biological effectiveness (RBE) values as a function of dose and irradiation time, we used a modified linear quadratic (LQ) approach, taking into account the ability of this new device, to deliver 20 Gy at the surface of a 40 mm diameter rigid, hollow spherical applicator in less than 2 minutes. In this study, we considered the radiobiological effectiveness of the Papillon + X-ray brachytherapy device operating at 30 kV, 0.3 mA producing dose rates in excess of 14 Gy/min. RESULTS: Calculated clinical RBEs ranged from 1.154 at the surface of a 40 mm diameter applicator to 1.100 at 35 mm from the applicator surface for the Papillon+ device. The absolute physical dose D (abs) 30 kV ranged from 20.00 Gy at the applicator surface to 1.20 at 35 mm distant. The product of the isoeffective single dose of (60)Co reference radiation - (RBE)(60)Co, and the RBE corrected standard 2 Gy equivalent dose fractions (EQD2) doses, EQD2(30 kV) * (RBE)(60)Co ranged from 98.62 Gy at the applicator surface to 1.13 at 35 mm. The 'shell of isoeffect', the value on the X-axis where the EQD2(30 kV) * (RBE)(60)Co line crosses the 50 Gy mark on the Y-axis, was found to be approximately 3.5 mm beyond the applicator surface. CONCLUSIONS: The 'shell of isoeffect' can serve as a useful metric with which to compare the radiobiological effectiveness of low kV eBT with various regimes of conventional EBRT.